In building construction, a newly installed or repaired operating sewage conduit in the building waste or sewer drainage system must frequently be isolated from the sewage service line until the plumbing construction is tested, inspected and certified. It is common practice within the construction industry to place an outlet end of a newly installed sewage conduit of the building at a juncture near an inlet to a sewage service line. During installation, these two lines are capped and not connected. Where these two lines would otherwise meet, each line is capped-off until testing and inspection is complete to meet building code requirements the system within the building usually must be subjected to a fluid pressure test to locate any leaks. As a result of usual construction techniques, the juncture is frequently buried before the tests are preformed. After testing and inspection is complete, the juncture is re-excavated, the caps removed, and a secure connection of the two lines is made.
Various patents have been issued disclosing test or isolation valve assemblies used in the inspection of the system prior to connection of the sewer line.
Sullivan U.S. Pat. No. 4,429,568, discloses a closure plug for pressure testing a liquid drain and vent plumbing type system. Sullivan uses a clean-out Y for access to open the plug plate assembly.
Cohen U.S. Pat. No. 1,720,819, discloses a test tee having a tapered gate which closes off a house drain pipe from a drainage system. After the test has been completed, the gate is removed from the test tee and the resulting opening in the tee is closed by a cover plate.
Tagliarnio U.S. Pat. No. 4,542,642, discloses a test tee having a plug which is a removable blocking disk. The blocking disk engages a ledge in the test tee and seals the drainage system. The diaphragm is accessible and removable through an access means.
Roberson U.S. Pat. No. 4,658,861, discloses a pneumatic plug inserted through a clean-out tee to block off a house service line to the main sewer line.
Kennedy U.S. Pat. No. 1,948,220, discloses a test plumbing system using a flap valve which is pivoted at an upper side of a valve seat. The flap valve is held in position by a valve adjusting rod.
Barber U.S. Pat. No. 4,602,504, shows a permanently installed test fitting in which a seal diaphragm has a frangible, removable portion which may be broken away from the diaphragm and removed to permit service use of the system. A portion of the seal diaphragm remains permanently in the conduit with its edge exposed.
The listed references relate to the general field of disclosure of this invention but many suffer from the permanent presence of apparatus in the conduit which can catch refuse and cause pluggage. The references are cited as the closest art of which the inventor is aware.